How can I change a var to the nearest number?

Question

I have two numbers wich can change, like x1 and x2. Then I also have an other number what is random but always between x1 and x2, like z. What I want to do is change z to the nearest x.

Sooo if I give you guys an example:

Input:

x1 = 12.24
x2 = 346.92
z = 274.45

Output:

z = 346.92

z is now 346.92 because that is the nearest number for z. This is what I am trying to do in Javascript. I thought there was no command for and you have to do it with just some math. I really have no idea how to do that... But there are you!

Thnx for all your help!

http://stackoverflow.com/questions/8584902/get-closet-number-out-of-array — adeneo, Mar 05 '15 at 16:44
So in your example above, z is 12.24 50% of the time and 346.45 50% of the time? — Chris Charles, Mar 05 '15 at 16:45
Does [my response](http://stackoverflow.com/a/28883285/3974585) helped you ? Its telling you which one is the nearest, and Z is a random number so you can try it multiple times just by running the code. I removed the JQUERY document ready, and it is now only javascript — Romain Derie, Mar 05 '15 at 17:03

score 0 · Accepted Answer · answered Mar 05 '15 at 16:46

0

How about this?

z = (Math.abs(z-x1)<Math.abs(z-x2))?x1:x2;

If you're sure x1 < x2, then:

z = ( (z-x1) < (x2-z) ) ? x1 : x2;

answered Mar 05 '15 at 16:46

lpg

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Thnx this is working fine! – Thomas Pereira Mar 05 '15 at 16:56

Romain Derie · Answer 2 · 2015-03-05T17:06:35.063

0

Here is a working jsFiddle With Math.abs(z - x1) and Math.abs(z - x2) you get the number between both values. Then you check if the first difference is bigger than the second.

x1 = 12.24;
x2 = 346.92;
z = Math.floor((Math.random() * 346) + 1);
z_ = z;
if (Math.abs (z - x1) < Math.abs (z - x2)){
  z = x1;
}     
else{
  z = x2
}
alert(z_ + " is closer to : "+ z);

Edit : Added a random number every time you run so you can see exactly how it works

edited Mar 05 '15 at 17:06

answered Mar 05 '15 at 16:51

Romain Derie

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Corrected that, thought it would be simplier to put the code into a document ready, but you are right the user didnt tag jquery – Romain Derie Mar 05 '15 at 17:01
Took the liberty of anglicizing your answer. This is an english-language website. – Jamiec Mar 05 '15 at 17:03
Yeah indeed, thanks for reminding, sometimes in code lines belgium is coming back :( – Romain Derie Mar 05 '15 at 17:05

score 0 · Answer 3 · answered Mar 05 '15 at 16:52

z = Math.round((z - x1) / (x2 - x1)) * (x2 - x1) + x1;

Whether x1 is greater than x2 or vice versa, this will consistently move z to the closer of the two.

How does it work?

(z - x1) / (x2 - x1)

Find the difference between z and x1 as a ratio to the difference between the two extrema.

Math.round((z - x1) / (x2 - x1))

Choose an extreme (1 or 0) based on proximity.

Math.round((z - x1) / (x2 - x1)) * (x2 - x1)

Multiple that extreme (1 or 0) by the difference between the two extrema.

Math.round((z - x1) / (x2 - x1)) * (x2 - x1) + x1;

Add the difference to x1, guaranteeing that the result is equivalent to either x1 or x2.

score 0 · Answer 4 · edited Mar 05 '15 at 17:03

0

Try:

z = (Math.abs(x1-z)>(Math.abs(x2-z)) ? x2 : x1);

edited Mar 05 '15 at 17:03

Jamiec

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answered Mar 05 '15 at 16:54

Mauro Cudicio

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7

score 0 · Answer 5 · answered Mar 05 '15 at 17:12

0

Just calculate the difference by substracting Z from x1, and x2:

if( (z - x1) < (x2 - z)){
  z = x1;
}else{
  z= h2;
}

If the values may get negative .. use Math.abs(z-x1) , Math.abs(x2-z) to get the ABSOLUTE value.

answered Mar 05 '15 at 17:12

d.raev

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score -1 · Answer 6 · answered Mar 05 '15 at 16:48

-1

If z is random and evenly distributed:

z = Math.random() > 0.5 : x1 ? x2;

answered Mar 05 '15 at 16:48

Chris Charles

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OP said it was 3 minutes ago. – Austin Mullins Mar 05 '15 at 16:51

How can I change a var to the nearest number?

6 Answers6